Yes, it was an amazing landing, an engineering triumph, a 150-million-mile slam dunk, spectacular in every way, except ... I think my grandpa would be disappointed. I'm not sure of this, since he died 50 years ago, but I have a hunch.

It starts with a handwritten letter he wrote back in 1907. He was a travelling salesman. He sold men's hats, and his job was to visit retailers all over the country. "One evening," he wrote, "train riding between Chicago and Kansas City or St. Louis, sitting the club car, I read a magazine, The Century..."

An article caught his eye. It was written by "Dr. Percival Lowell, Harvard, in charge of the Flagstaff Observatory". It was about Mars, and whatever Lowell said, my grandfather was wowed. It "opened my eyes", he writes.

Hmmm. I figured it shouldn't be hard to read what my grandpa was reading, so I put "Percival Lowell", "The Century" and "1907" into a browser up it popped: "Mars as the Abode of Life," yes, written by Lowell, and oh wow! What a story he told my grandfather!

Lowell had built an observatory in Arizona, had spent his nights surveying the red planet, had found evidence of some enormous construction project visible on Mars with lines of "surprising straightness," "amazing uniformity,"and "immense length" that persisted over the months.

Lowell was more storyteller than scientist. He ignored technical issues like the thinness of the Martian atmosphere, the different chemistry of its air, and concentrated instead on the drama building in his head.

Lowell decided that creatures on Mars — he didn't call them human, all he would say is that they could plan, organize and build on a global scale, were running shy of water, and getting increasingly thirsty. The planet, he said, showed evidence of drying, and these entities, to stay alive, had built a series of structures to move water from the melting poles to inhabited regions near the Martian equator.

He called them "canals" — this at a time when engineers on Earth had just built the Suez canal, and were still building the Panama canal. Canal building was hot, hot, hot technology in the early 20th century, and these Martians were designing on a scale that dwarfed human accomplishment, suggesting to him that not only is "Mars at this moment inhabited," but these canal builders were "of an order whose acquaintance was worth the making" — if we could get to them in time, before they perished.

From what he could tell, he told his readers, Martian life was at that very moment winking out, that these canal builders would soon die of thirst, there was no present way to span the distance between the two planets, so these remarkable neighbors he had just discovered would, "cosmically speaking, soon ... pass away." Civilization on Mars, Lowell thought, "...has not long to last," and all we could do is watch them contend with their fate across the void — and perish.

I don't know if my grandfather believed all of Lowell's narrative, but from the rest of his letter, I can tell he didn't overtly challenge the premise, that there were other intelligent creatures in the solar system, not mentioned in the Bible (that was, for my grandfather, a sore point) and that all this had "opened his eyes."

That was 1907. More than a hundred years have passed. Today, the stories we tell about Mars have gotten, or seem to have gotten, umm, smaller.

Lowell's canals turned out to be illusions. Two probes in 1976 found no convincing sign of Martian life, at least not on the planet surface. There remains the possibility that there is life under the ground on Mars, or failing that, that there was once life there, millions of years ago. The life we're imagining now is not a tool-making, canal building intelligence, but something more modest: a one celled carbon-based critter that lived in water and then died. Or maybe a methanogen, a bacteria that pooped (or still poops) gas.

A one ton machine has been plopped onto a low plain where water would have once been, and as my NPR colleague Joe Palca carefully and elegantly points out (when I grow up, I want to be Joe Palca), our goal is not to find Martian life, but rather to find building blocks of life, to see if life on Mars is or was possible.

We're not hunting for a Martian. We're not looking for a live body (or even a dead one). We are hunting for chemical traces that might have once supported the existence of a single-celled Martian — maybe.

Ah, the difference a century makes.

What's The Point?

But if my grandfather were to lean across the seat in his club car and say, "Why bother?" I'd say to him with the same breathlessness of Percival Lowell, we still want to know what you wanted to know: Are we alone? Are we the only ones? Is there life anywhere else? Even if we can't talk to it, pity it, admire it or fear it, still, any "it" would be a revelation.

"It" may have been our ancestor. Some "Its" from Mars might have bounced to Earth and become the seed of us. "It" may have started there, stayed there, died there, but at least we know it was there, which means life can happen in more than one place. "It" may have a different chemistry, a different logic than we do, in which case, we have evidence of truly alien life forms.

"It's" story may be less operatic than Lowell's version, but if there ever was an "It", no matter how simple, how small, I want to know. We all do. Even (if he doesn't know already wherever he may be) my Grandpa.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.